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DIEL VARIATION IN ECHOLOCATION BEHAVIOR OF WILD HARBOR PORPOISES
Julia Carlström
Marine Mammal Science: Vol. 21, No. 1, pp. 1-12.
Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden
E-mail: [EMAIL PROTECTED]
ABSTRACT
The echolocation rate and behavior of wild harbor porpoises were studied
using a harbor porpoise click detector (POD) deployed close to the bottom
at 40 m depth in Scottish waters, UK, April-June 2001. Echolocation
variables were compared among four diel phases; morning, day, evening, and
night. The echolocation encounter rate, the minimum interclick interval per
train, and the proportion of echolocation click trains with a minimum
interclick interval below 10 msec were all significantly higher at night
than during the day. The variation in echolocation rate implies that
porpoises increased their echolocation rate and/or visited the depth of the
POD more often at night than during the day. Further, the changes in
minimum interclick interval per train suggest that they used their
echolocation for foraging or investigating objects at a close range to a
higher extent, and acoustically explored the environment at greater
distances at night than during the day.
Keywords: harbor porpoise, Phocoena phocoena, echolocation, behavior,
foraging, detection distance, click train, diel, click detector.
BUBBLESTREAM WHISTLES ARE NOT REPRESENTATIVE OF A BOTTLENOSE DOLPHIN'S
VOCAL REPERTOIRE
Deborah Fripp
Marine Mammal Science: Vol. 21, No. 1, pp. 29-44.
Department of Biology, Woods Hole Oceanographic Institution, Woods Hole,
Massachusetts 02543, U.S.A.
E-mail: [EMAIL PROTECTED]
Corresponding address: 3826 Cemetery Hill Rd, Carrollton, Texas 75007, U.S.A
ABSTRACT
Whistling bottlenose dolphins sometimes identify themselves with a
concurrent bubblestream, and some researchers use these bubblestream
whistles as their sole whistle sample. However, bubblestream whistles are
not known to be representative of the entire repertoire. Bubblestreams and
whistles were recorded from three captive female dolphins and their newborn
calves. Bubblestreams were rare (0.13/min), with calves producing ten times
as many as adults. Overall, 79% of bubblestreams were associated with
whistles, but only 1% of whistles were associated with bubblestreams.
Bubblestream whistles were not independent: 49% occurred within 1 sec of
another bubblestream, and 72% of these had the same contour as other
bubblestream whistles in the bout. Bubblestream use was context-dependent:
adults were more likely to bubblestream when caring for a calf (P < 0.001),
and calves were more likely to bubblestream when other calves were present
(P < 0.001). Bubblestreams were not associated with all whistle types.
Bubblestream whistles were not evenly distributed across the clusters of a
hierarchical cluster analysis of contour parameters using 300 randomly
selected non-bubblestream whistles and 92 independent bubblestream whistles
(10 clusters, P = 0.003). In conclusion, bubblestreams are rare visual cues
that dolphins produce in association with certain whistles in certain
contexts and are not representative of the dolphin's repertoire.
Keywords: bottlenose dolphin, Tursiops truncatus, cetacean, bubblestream,
vocal behavior, whistle samples, maternal behavior, calf behavior, whistle
collection.
VOCALIZATIONS OF A FEMALE HUMPBACK WHALE IN ARRAIAL DO CABO (RJ, BRAZIL)
Sheila M. Simão and Sergio C. Moreira
Marine Mammal Science: Vol. 21, No. 1, pp. 150-153.
Cetacean Bioacoustics Lab - UFRRJ/IF/DCA, P. O. Box 74544, Seropédica, Rio
de Janeiro, 23851-970, Brazil E-mail: [EMAIL PROTECTED]
No abstract available.
**This listing does not include NOTES to the journal which are not posted
on the website ***
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